Cn-Symmetric Metasurfaces for Spatial and Temporal THz Control
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Solution Overview
Problem
Generating and configuring terahertz radiation for various applications is a complex and costly endeavor, hindering the adoption of THz technologies.
Innovation Solution
The use of nonlinear metasurfaces (NLMs) comprising arrays of subwavelength antennas with rotational symmetry, which are illuminated by linearly or circularly polarized radiation to generate and control the spatial and temporal shape of THz radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional methods are used to generate and configure THz radiation, then the desired spatial and temporal control of THz radiation can be achieved, but the system complexity and cost increase significantly
Solution Approach 1:
The patent divides the THz radiation control function into discrete subwavelength antenna elements arranged in arrays. Each antenna element can be independently controlled, allowing complex spatial and temporal configurations to be achieved by coordinating simple individual elements rather than using a single complex device
Solution Approach 2:
The patent introduces temporal dimension by using femtosecond laser pulses to excite the antennas, enabling dynamic control of THz radiation in both space and time. The subwavelength antennas are excited by ultrashort laser pulses to generate THz radiation with controlled temporal profiles
2Ease of operation
If traditional methods are used to generate and configure THz radiation, then the desired spatial and temporal control of THz radiation can be achieved, but the equipment cost increases significantly
Solution Approach 1:
The patent replaces complex mechanical THz generation systems with an optical-based approach using femtosecond laser excitation of subwavelength antennas. This substitution eliminates the need for expensive mechanical equipment while achieving precise control through optical fields
Solution Approach 2:
The patent changes the operating parameters by using subwavelength antenna dimensions much smaller than the THz wavelength, enabling efficient radiation control. The antennas are excited by ultrashort laser pulses with specific temporal and spectral characteristics to generate desired THz waveforms
3Adaptability or versatility
If subwavelength antennas with rotational symmetry are used, then the spatial and temporal shape of THz radiation can be controlled, but the antenna design complexity increases
Solution Approach 1:
The patent uses subwavelength antennas with rotational symmetry (Cn symmetry) where n≥3. This specific symmetric design allows the antennas to generate circularly polarized THz radiation and control the spatial distribution of radiation through the symmetry order, achieving versatile control while maintaining geometric simplicity
Solution Approach 2:
The subwavelength antennas with rotational symmetry serve multiple functions: they generate THz radiation, control polarization states, and shape spatial distribution patterns. This multi-functionality is achieved through a single antenna geometry design rather than requiring separate components for each function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the efficient generation and control of THz radiation with desired temporal and spatial configurations, overcoming the complexity and cost associated with traditional methods.
Implementation Method 1
The subwavelength antennas may be excitable by relatively low energy femtosecond pulses of, optionally near infrared (NIR), linearly or circularly polarized pump radiation to generate and radiate THz radiation
Implementation Method 2
the array of subwavelength antennas is configured to generate and radiate THz radiation for which linear polarization of the THz radiation may be controlled by controlling direction of polarization of the NIR pump radiation exciting the array
Implementation Method 3
The Cn subwavelength antennas in the array, also referred to as a rotation array, may be configured to exhibit, optionally continuous, angular change in their orientation with displacement along a straight or curved spatial modulation directrix
Data Source
AI summary
Apparatus for generating THz (terahertz) radiation, the apparatus comprising: a substrate; a planar array of subwavelength antennas formed on the substrate having rotational symmetry, Cn, of order “n” greater than or equal to 3 and rotational symmetry cycle 2π/η, which are excitable by near infrared (NIR)_pump radiation to radiate THz radiation having wavelengths that are substantially larger than characteristic dimensions of the subwavelength antenna; wherein the array comprises a plurality of sections each comprising plurality of subwavelength antennas exhibiting a spatial pattern different from that of an adjacent section of the plurality of sections.